Enhanced adsorption capacity of cryogel bed by incorporating polymeric resin particles

Novel composite cryogel monoliths were fabricated by incorporating polymeric resin particles and grafting anion-exchange groups on the pore wall surfaces. The embedded resin particles in different size distributions were prepared by grinding poly(glycidyl methacrylate–ethylene glycol dimethacrylate) monoliths. Observations by scanning electron microscopy clearly indicated that the composite cryogel had interconnected large pores (10–100 μm in width), similar to normal (pure) cryogel. However, the composite material had very rough pore walls, which provided larger surface area for protein adsorption. As a result, the dynamic binding capacity of bovine serum albumin (BSA) on the composite cryogel bed reached 6 mg/mL bed (flow velocity, 5 cm/min), which was 2.8 times higher than a cryogel bed without embedding the ground resin particles. The capacity value was also much higher than the BSA capacities of cryogel beds reported in literature (1–4 mg/mL). Though the capacity decreased by about 1 mg/mL with the increase of flow rate from 0.5 to 5 cm/min, it then kept almost unchanged till a flow rate up to 15 cm/min. The height equivalent to a theoretical plate of the composite bed was in the range of 1.1–1.4 mm, and kept nearly constant in a flow rate range of 5–20 cm/min. The results indicated that the composite cryogel bed offered a large improvement in protein adsorption capacity and was suitable for high-speed protein chromatography.